The leak never posed a threat to the community, said Arizona Public Service spokesman Alan Bunnel. “It is radioactive water, but because it’s inside the steel and concrete containment dome there was no threat of any radioactive material coming outside into the environment,” Bunnel said. “There was no threat to the safety or well being of the public or employees.”

Brenner said they found the small leak at Palo Verde as a result of NRC-mandated inspections.

Meanwhile, Dominion Virginia Power returned North Anna Power Station’s Unit 1 nuclear reactor in Mineral, VA, to service Sunday afternoon.

The utility tried to return the 948-megawatt reactor to service last Thursday following a scheduled refueling and maintenance outage, but an automatic shutdown occurred Friday afternoon after it reached 48 percent of power.

Richmond, VA-based Dominion said the cause of the shutdown at the Louisa County plant was a protection relay associated with a station service transformer not returned to its proper operational configuration. Service transformers at North Anna move electricity from the grid to power electrical systems required for normal station operation.

One-third of the reactor fuel ended up replaced with new fuel during the outage, and officials performed a number of maintenance activities. In addition, station personnel installed mechanical and electrical tie-in connections for hoses and external power supplies they could use in an emergency to provide cooling water and electricity to the facility.